Later this month, the Obama administration will unveil a new strategy for the war in Afghanistan. This comes as most important indicators in Afghanistan are pointing in the wrong direction. President Obama's decision last month to deploy an additional 17,000 U.S. troops was an important step in the right direction, but a comprehensive overhaul of our war plan is needed, and quickly.

As the administration finalizes its policy review, we are troubled by calls in some quarters for the president to adopt a "minimalist" approach toward Afghanistan. Supporters of this course caution that the American people are tired of war and that an ambitious, long-term commitment to Afghanistan may be politically unfeasible. They warn that Afghanistan has always been a "graveyard of empires" and has never been governable. Instead, they suggest, we can protect our vital national interests in Afghanistan even while lowering our objectives and accepting more "realistic" goals there -- for instance, by scaling back our long-term commitment to helping the Afghan people build a better future in favor of a short-term focus on fighting terrorists.

The political allure of such a reductionist approach is obvious. But it is also dangerously and fundamentally wrong, and the president should unambiguously reject it. Let there be no doubt: The war in Afghanistan can be won. Success -- a stable, secure, self-governing Afghanistan that is not a terrorist sanctuary -- can be achieved. Just as in Iraq, there is no shortcut to success, no clever "middle way" that allows us to achieve more by doing less. A minimalist approach in Afghanistan is a recipe not for winning smarter but for losing slowly at tremendous cost in American lives, treasure and security.

Yes, our vital national interest in Afghanistan is to prevent it from once again becoming a haven for terrorists to plan attacks against America and U.S. allies. But achieving this narrow counterterrorism objective requires us to carry out a far broader set of tasks, the foremost of which are protecting the population, nurturing legitimate and effective governance, and fostering development. In short, we need a comprehensive civil-military counterinsurgency approach backed by greatly increased resources and an unambiguous U.S. political commitment to success in Afghanistan over the long haul.

A narrow, short-term focus on counterterrorism, by contrast, would repeat the mistakes made for years in Iraq before the troop surge, with the same catastrophic consequences. Before 2007 in Iraq, U.S. Special Forces had complete freedom of action to strike at terrorist leaders, backed by more than 120,000 conventional American forces and overwhelming air power. Although we succeeded in killing countless terrorists -- including the leader of al-Qaeda in Iraq, Abu Musab al-Zarqawi -- the insurgency continued to grow in strength and violence. It was not until we changed course and applied a new approach -- a counterinsurgency strategy focused on providing basic security for the people and improving their lives -- that the cycle of violence was at last broken.

Those who argue for simply conducting targeted counterterrorist strikes in Afghanistan also fail to grasp that by far the best way to generate the intelligence necessary for such strikes is from Afghan civilians, who will risk their lives to help us only if they believe we are committed to staying and protecting them from the insurgents and helping to improve their lives.

Loose rhetoric about a minimal commitment in Afghanistan is counterproductive for another reason: It exacerbates suspicions, already widespread in South Asia, that the United States will tire of this war and retreat. These doubts about our staying power deter ordinary Afghans from siding with our coalition against the insurgency. Also important is that these suspicions are a major reason some in Pakistan are reluctant to break decisively with insurgent groups, which, in a hedging strategy, they view as integral to positioning Pakistan for influence "the day after" the United States gives up and leaves Afghanistan. That is why it is so important for the president to reject the temptations of minimalism in Afghanistan and instead adopt a fully resourced, comprehensive counterinsurgency strategy, backed by an unambiguous American commitment to success over the long term. In doing so, he must invest the political capital to remind Americans why this fight is necessary for our national security, speak openly and frankly to our nation about the difficult path ahead, and -- most of all -- explain clearly to our fellow citizens why he is confident that we can prevail.

As a presidential candidate, Barack Obama called Afghanistan "the war we must win." He was absolutely right. Now it is time to win it -- and we and many other members of both political parties stand ready to give him our full support in this crucial fight.

John McCain, a Republican senator from Arizona, was the 2008 Republican nominee for president. Joe Lieberman, an Independent Democratic senator from Connecticut, was the Democratic nominee for vice president in 2000.